My impression is that at T-24 you should be OK to get Aisle seats

What you can do is use the free version of expert flyer to do seat alerts on your flight to see what is occupied (d not worry so much about blocked)

expertflyer.com

You can also use expert flyer over the next few days to monitor the availability of seats on flights "in the next 24 hours", but again do not worry too much about the blocked seats, just the occupied. At T-72 you will see lots of seats become blocked and then as more people check in more blocked seats are made available.

However if you think you will not be able to check in around t-24 or T-22 it may become more difficult.

cws has posted info previously about roughly how many people check in at what time and may do so again, your EDI will likely be a bit more status heavy than those numbers but should still be ok. You would be unlucky if two thirds of the flight has picked seats and only picked windows and aisles